Measurement of $\ddot{I}{‡}_{c1}(3872)$ production in proton-proton collisions at $\sqrt{s}=8$ and $13$ TeV

Abstract

The production cross-section of the $\ddot{I}{‡}_{c1}(3872)$ state relative to the $\ddot{I}ˆ(2S)$ meson is measured using proton-proton collision data collected with the LHCb experiment at centre-of-mass energies of $\sqrt{s}=8$ and 13 TeV, corresponding to integrated luminosities of 2.0 and 5.4 fb${}^{-1}$, respectively. The two mesons are reconstructed in the $J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ final state. The ratios of the prompt and nonprompt $\ddot{I}{‡}_{c1}(3872)$ to $\ddot{I}ˆ(2S)$ production cross-sections are measured as a function of transverse momentum, $p_{\mathrm{T}}$, and rapidity, $y$, in the kinematic range $4<p_{\mathrm{T}}<20$ GeV/$c$ and $2.0<y<4.5$. The prompt ratio is found to increase with $p_{\mathrm{T}}$ independently of $y$. The double-differential cross-section ratio of $\ddot{I}{‡}_{c1}(3872)$ relative to $\ddot{I}ˆ(2S)$ mesons between 13 and 8 TeV is also measured for the prompt component and observed to be consistent with unity, independent of $p_{\mathrm{T}}$ and centre-of-mass energy.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-026.html (LHCb public pages)